CIRCULATING GROWTH-HORMONE (GH), INSULIN-LIKE GROWTH-FACTOR-I (IGF-I)AND FREE-THYROXINE, GH RESPONSE TO CLONIDINE PROVOCATION AND CT SCANNING OF THE HYPOTHALAMIC-PITUITARY AREA IN CHILDREN WITH SICKLE-CELL DISEASE

Serum growth hormone (GH), cortisol, free thyroxine (FT4), thyroid-sti mulating hormone (TSH), and insulin like growth factor I (IGF-I) conce ntrations were measured in 15 children with sickle cell disease (SCD) together with their heights < 5th percentile for age and gender, and i n 15 healthy age-matched children who had normal variant short stature (NVSS), GH response to an oral dose of clonidine (0.15 mg/m(2)) and c ortisol response to ACTH stimulation were determined in the two groups . Children with SCD had significantly lower serum concentrations of IG F-I and decreased GH response to stimulation. Eight out of the 15 chil dren with SCD did not mount an appropriate GH response to clonidine pr ovocation (> 10 mu g/l). CT scanning of the hypothalamic-pituitary are a in those eight children with SCD revealed a partial or complete empt y sella in all of them. It appears that defective GH release, and cons equently low IGF-I production and slow growth velocity in children wit h SCD might be secondary to hypoxic-vascular insults to their hypothal amic-pituitary axis during one or more of the sickling episodes.